SnowCal is a simple programming language used to perform calculations. A SnowCal program keeps a single integer X in memory, initially set to zero, and repeatedly performs addition and multiplication operations on it. Formally, the language has 5 operations:
- ADD Y → add Y to X
- MUL Y → multiply X by Y
- FUN F → begin the definition of a function with unique name F
- END → end of current function
- INV F → invoke function F
Write an interpreter that takes in the commands as an array of strings and returns the final value of X.
Example Programs
Input:
MUL 2
ADD 3
Output:
3
Input:
FUN INCREMENT
ADD 1
END
INV INCREMENT
MUL 2
ADD 3This problem asks you to implement an interpreter for a simplified programming language called SnowCal, which maintains a single integer X in memory (initially 0). The language supports five commands:
ADD Y→ addYtoXMUL Y→ multiplyXbyYFUN F→ begin defining a user-defined function namedFEND→ end of the current functionINV F→ invoke functionF
You must parse the program line-by-line, store any function definitions, and correctly execute operations (including nested or repeated function calls). The output is the final value of X after processing all commands.
Core challenges include:
- Managing function definitions and scopes
- Handling function invocation correctly
- Ensuring commands execute sequentially
- Avoiding recursion issues if functions call each other
This tests a candidate’s ability to design an interpreter, manage state, and implement clean parsing and execution logic.
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